1. Field of the Invention
The present invention relates to a bonding strength testing device. More particularly, the present invention relates to a bonding strength testing device for testing the strength of a solider ball.
2. Description of the Related Art
With the rapid progress in electronic technologies, more personalized and functionally powerful electronic products are out in the market. In general, a list of tests needs to be performed on any fully packaged electronic product before shipment. The list of tests for ensuring the yield and quality of the electronic product includes, for example, an aging test, an electrical test, a pull test, a solder ball impact test and so on. Using the solder ball impact test as an example, two types of bonding strength testing devices are commonly deployed by manufacturers to test the bonding strength of solder balls. FIG. 1 is a schematic cross-sectional view of a conventional bonding strength testing device. The method of testing the bonding strength using the bonding strength testing device 100a in FIG. 1 includes raising the swinging pendulum 110 to a height H0 and then letting go of the swinging pendulum 110. The swinging pendulum 110 impacts the solder ball 130 implanted in the substrate 120. When the solder ball 130 breaks away from the substrate 120, a portion of the energy of the swinging pendulum 110 will be absorbed so that the remaining energy permits the swinging pendulum 110 to rise to another height H1 at the other end. Knowing the weight of the swinging pendulum 110 and the difference in height between H0 and H1, the amount of energy needed to break the solder ball 130 can be calculated.
FIG. 2 is a schematic cross-sectional view of another conventional bonding strength testing device. The method of testing the bonding strength using the bonding strength testing device 100b in FIG. 2 includes driving the push rod 140 to a constant speed (for example, about 300 m/s). Then, the push rod 140 impacts the solder ball 130 on the substrate 120 until the solder ball 130 breaks away from the substrate 120. However, this type of bonding strength testing device 100b can analyze the damaging mode of the solder ball 130 only. Furthermore, with the stress sensor 150 and the solder ball 130 separated from each other by a relatively large distance, overall sensitivity of the test is usually poor. Therefore, the stress sensor 150 can hardly obtain an accurate profile of the impact response of the solder ball 130.